Design Of Semiconductor Laser Driver System Based On STM32

The rapid development of laser technology has greatly enhanced the electro-optical conversion efficiency and output optical power of semiconductor lasers,leading to their widespread application in various fields.However,the central wavelength and output power of semiconductor lasers are easily affected by the driving current and working temperature.To ensure stable driving current and working temperature of the semiconductor laser,and provide accurate,reliable and stable laser source performance for subsequent remote sensing,this thesis has designed a set of driving systems for medium-low power semiconductor lasers using STM32 technology.The semiconductor laser driving system presented in this thesis integrates power control and temperature control functions,utilizing STM32 as the main control chip.Firstly,to stabilize the working temperature of the semiconductor laser,STM32 reads the temperature data collected by the thermistor integrated inside the laser through AD conversion.Subsequently,it employs an H-bridge driver chip and PID algorithm to control the working state of the semiconductor refrigeration chip integrated inside the laser.This ensures real-time control of the laser’s working temperature.Secondly,in terms of driving current stability control of semiconductor lasers,a constant current source circuit was designed based on the deep negative feedback principle.Finally,in the stability control of the semiconductor laser output power,the power control capability of both constant voltage control and constant power control.We determined the optimal power stability control method and combined it with the constant current source circuit to form a double-closed loop control system.This enabled us to achieve reliable control of both the laser output power and the central wavelength stability.After completing the hardware and software system design,we performed experimental performance tests on the semiconductor laser,which included various performance indicators such as working temperature,driving current,output power,and central wavelength.The experimental results show that the stability of the driving current of the semiconductor laser operating for one hour is about 0.3%,and the linearity is 0.86%.The long-term working temperature control accuracy is ±0.03°C,and stability can be achieved up to 0.18%.Compared with integrated temperature control chips,this design has a faster temperature adjustment speed,better control algorithm optimization space,and more convenient temperature setting.In terms of power stability control,a constant voltage control method can obtain more stable output power and central wavelength.Laser output power stability is within ±2m W,and the stability of output power is 0.44%,and the fluctuation range of the central wavelength is only 0.0075nm.